Audubon's Oriole
Encyclopedia
Audubon's Oriole is a New World passerine inhabiting the forests and thickets of southeastern Texas and the Mexican coast. It is the only species to have a black hood and yellow body. It is divided into four subspecies and two allopatric breeding ranges. The westernmost range extends from Nayarit
south to southern Oaxaca
, whereas the eastern range stretches from the lower Rio Grande valley to northern Querétaro
. Most common in the western range are the subspecies I. g. dickeyae and I. g. nayaritensis; I. g. graduacauda and I. g. audubonii can be found in the eastern range. Like most Central American birds, it is not a migratory species and does not display significant sexual dimorphism
. DNA analysis of the ND2 and cyt-b
genes strongly suggests that I. graduacauda is most closely related to I. chrysater, the Yellow-backed Oriole
. It is a member of the genus Icterus
and therefore should not be confused with the Old World orioles.
The nest of the Audubon's Oriole is similar in size and construction to those of the Hooded and Orchard Orioles, being approximately three inches in diameter with a similar depth. The nests are bag-shaped and semi-pensile; that is, they are usually found on the outer twigs of trees, rather than against the trunk.
A mating pair of orioles usually incubates two broods per year, each consisting of between three to five eggs per brood; however, chicks hatched from the later brood are usually unable to survive the winter. This species' nests are often parasitized by the Bronzed Cowbird
.
Nayarit
Nayarit officially Estado Libre y Soberano de Nayarit is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 20 municipalities and its capital city is Tepic.It is located in Western Mexico...
south to southern Oaxaca
Oaxaca
Oaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
, whereas the eastern range stretches from the lower Rio Grande valley to northern Querétaro
Querétaro
Querétaro officially Estado Libre y Soberano de Querétaro de Arteaga is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 18 municipalities and its capital city is Santiago de Querétaro....
. Most common in the western range are the subspecies I. g. dickeyae and I. g. nayaritensis; I. g. graduacauda and I. g. audubonii can be found in the eastern range. Like most Central American birds, it is not a migratory species and does not display significant sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
. DNA analysis of the ND2 and cyt-b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
genes strongly suggests that I. graduacauda is most closely related to I. chrysater, the Yellow-backed Oriole
Yellow-backed Oriole
The Yellow-backed Oriole is a species of bird in the Icteridae family.-Physical description:Yellow-backed orioles are a yellow-bodied, sexually monomorphic species. Howell and Webb note that this species tends to average 21.5 cm in length from beak to tail; making Icterus chrysater a...
. It is a member of the genus Icterus
New World oriole
New World orioles, comprising the genus Icterus, are a group of birds in the blackbird family. They are not related to Old World orioles which are in the family Oriolidae, but are strikingly similar in size, diet, behaviour and in their strongly contrasting plumage, and are a good example of...
and therefore should not be confused with the Old World orioles.
Description
The male of the species has a black hood, mandible, and throat, as well as a black tail. Wings are black, but the remiges and retrices (flight feathers) are fringed with white. The secondary coverts form yellow epaulets. The back and vent are yellow washed with olive, and the underside is almost uniformly yellow. Females of this species have a slightly more olive nape and back than the males. The adult female's (first-definitive) plumage is similar to the juvenile plumage; however, unlike adults, the wings are dull brown instead of black. In general, immature specimens have the hood; wingbars; remiges; and epaulets of adult specimens. The first-basic plumage retains the darker, greener coloration of the juvenile plumage, however. Molting generally occurs in early autumn, though some specimens have been noted to molt as early as June.Behavior
Audubon's Oriole inhabits dense evergreen forests and thickets, preferring riparian (riverside) areas. Though it prefers the shade, mating pairs may occasionally spotted foraging in clearings. In flight, it joins mixed-species flocks that include orioles, jays, tanagers, and other birds of similar size.The nest of the Audubon's Oriole is similar in size and construction to those of the Hooded and Orchard Orioles, being approximately three inches in diameter with a similar depth. The nests are bag-shaped and semi-pensile; that is, they are usually found on the outer twigs of trees, rather than against the trunk.
A mating pair of orioles usually incubates two broods per year, each consisting of between three to five eggs per brood; however, chicks hatched from the later brood are usually unable to survive the winter. This species' nests are often parasitized by the Bronzed Cowbird
Bronzed Cowbird
The Bronzed Cowbird , Molothrus aeneus, is a small icterid.It breeds from the southern U.S. states of California, Arizona, New Mexico, Texas, and Louisiana south through Central America to Panama. An isolated population on the Caribbean coast of Colombia is sometimes treated as a separate species,...
.
Subspecies dickeyae
The subspecies I. g. dickeyae is of note because of the differences in appearance, behavior, and phylogeny between it and the other subspecies of I. graduacauda. The olive wash is weaker, making the bird more proportionally yellow than others of its species. In addition, the yellow epaulets are diminished in dickeyae, being confined to the lesser coverts.Further reading
- Flood NJ. (1990). Aspects of the Breeding Biology of Audubon's Oriole. Journal of Field Ornithology. vol 61, no 3. p. 290-302.
- Hobart HH, Gunn SJ & Bickham JW. (1982). Karyotypes of 6 Species of North American Blackbirds Icteridae Passeriformes. Auk. vol 99, no 3. p. 514-518.
- Monk S. G. M.S. (2003). Breeding distribution and habitat use of Audubon's oriole in the Lower Rio Grande Valley of Texas. The University of Texas - Pan American, United States.
- Patrikeev, Michael, Jack C. Eitniear, Scott M. Werner, Paul C. Palmer (2008) Interactions and Hybridization between Altamira and Audubon's Orioles in the Lower Rio Grande Valley BirdingBirding (magazine)Birding is the bimonthly members' magazine of the American Birding Association. While not a formal journal, Birding offers enthusiasts in-depth and scholarly articles on field identification and bird conservation. Each issue also features tips on North American and foreign birdfinding, news in the...
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